Process and apparatus for simultaneously drawing and plating wire



Sept. 1 1, 1956 H. KENMORE ETAL 2,762,763 PROCESS AND APPARATUS FOR SIMULTANEOUSLY DRAWING AND PLATING WIRE Filed July 13, 1951 2 Sheets-Sheet l IN VENT 0R3 N flan e-er KE /we M40191? J. l Ia M 57% Am. 477' KIVEKS PROCESS AND APPARATUS FOR SMULTANE- OUSLY DRAWING 'ANDFPLATING WM Herbert Kenmore and Walter]. Manson, ,Jersey City,

N. 'J., assignors,.by mesne assignments, to National- Standard Company, Niles, Mic'h., a corporation of Delaware Application July 13, 1951,.- Serial -No. 236, 663

3 Claims. (Cl. 204-28) of the wire between a die and a'take-up block which is spaced a suflicient distance'from thedie tojpermit' 'theaddition of cleaning, rinsing, -'el'ectroplatin'g, and other reqnired baths between saiddieand the takem'p block. The

. by continuously stretching a portion= of amoving' -leng'th wire is passed through these'baths without contacting-electrodes or guide rollers except that-'at-one-or more'poi'nts the wire is struckat'regular intervals to cause it' tolvibrate.

The tension or-stress applied'to'the wire is'equivalent to that which is sufiicient todraw the' wi're through adie which reduces itsdiameter and is-approximately-25-90'% of the tensile .strength of the wire. Other-Wire redhcihg means such as a pair of grooved rollers may be'subs'tituted for the die but it is noted that-the stress applied by a die is not only of the desired degree but it is also "av'ei'y uniform one. The contact with'the' electrodes' is avoided by placing the anode and the cathode of thefgenerator in two separate baths such as an electrolytic cleaning bath and the electroplating ba'th "wher'eby the-current passes from the anode in the plating baththroughthe-said bath along the wire, and through the cleaning bath to the cathode in the said cleaning bath without'direct contact between the wire and the electrodes. This idea of noncontacting electrodes is known bu-tin this invention the idea cooperates with the other features-thereof to enable the take-up block to apply a uniformliigh tensiontto 'the wire to draw the same through the die and the-bathsand to enable the vibrations induced by..striking :the :wireto extend all through the plating bath. In order to effectively apply a vibrating (force to the wire-while being treated, contacts and guide rolls have to beavoided incon bfi een the baths but guide rolls maybe inserted between the die and the first bath or between the last bath and the drawing means. The same tanks can be constructed so as to electroplate a number of wires simultaneously.

The novel features characteristic of this invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best 'be understood from the following description of specific embodiments when read in connection with the accompanying drawings in which:

2,762,763 Pat'ente'dfiept. 11, 1 956 HgSJ'I-A and-I B together form a cross sectional side "-view- 'of cme' -formof the apparatus.

Fig. 2'is a -top plan view 'of the apparatus of Figs. 1A wand '1B-:'wi'th some-of the baths omitted.

iEig. 3 is a-Iletail view partlyin cross section ofone lbatlv'with its-liquidcirculating system.

Fig. 4 is-a detail view-of a typical drawing die.

JA's'shoWn i-n' Figs. l-A, 1B and 2 the wire "100 is drawn throughaa die' IO, and pulled through-the-dieand the series I 1:. dfitbaths 20, 30, 40, $0, 60, and by talke-blocks'l-Z,

-218,'=14for15. The take-up blocks12, 13,"1'4-and 15-are Ion :aJevl with theou'tlet opening 'of'the particular'die from which they pull the-wire so that the wire travels 'in a substantiallystraighthorizon-tal path. According to the present invent-ion the-die and drawing blocks have been spaced -a distanceof 'over 30 feet, although it is obvious tha'tthe distance between the die and the drawing'blocks=Will depend-on the length ofthe baths through -'.which"the-wire is to be passed. A guide roller or-sirnilar "guide Jmeans -could be inserted between the die 10 and rthe first-bath.

LAsuitable Sequence-ofba'ths is shown in Figs. 1A and lBnthebath -20 bei'ng'a heated electrolytic cleaning bath, bath=='4tl=containing an'acid dip ,-bath 60 being the electroplating' bath and' ba th fitl being a'hot water bath 'for dryinglthe wire; Theserelativ'ely long baths 20,40, 60 and L r80ihave-shor-ter'rinsing b'aths 30, 50 and '70 therebetween -zwhich are-continuously'fed-with a-stream of ordinary-tap :-water.

ffldi'e various bathsare constructed in such a way that 'thewwire can -be fed therethrough in a substantially -straight horizontal p'ath under tension while said wire is :completely immersed in the bath liquid. As shown in Figure 3, the 'bath40"-has slits-41,42 at the ends thereof which-are somewhat-wider than the diameter of thewire 2100. Adjacent 'eaeh of -the slitted ends of the bath structture is a 'trough 43 or '44 adapted to catch the bath liquid which flows throughsaid -slits 41, 42. This overflow iliquid caughtdntroughs '43, -44, drains into the storage -tank118 through conduits 45,46-and from the storage tank --48 isspumped by pump=49-1through conduit 47 back into the'flaath 40. lhedi'quid is pumped back into bath 40 aat= a sufficient'rate tomaintain'the liquid level 101 of the :bath' above the top surfaceof the wire 100. In'the case =oftherinsing baths 30, 50 and 70 the recirculating sys- "-tem can be omitted.

The other baths 30, '40, 50, 60, 70,80, are constructed similarly to bath 40. 'Bath 20, for example, contains "similar-'slits=2 1,,22, troughs 23, 2'4, drainage connections '25,Z26-and supply conduit'27. Other methods of constructing the supply conduits, collecting troughs, etc., so as not to interfere with 'the'passage of the wire through .ltherba-ths and yet-:assure t-he 'completersubmersion of the -'wire'.could:-be employed. Additional methods are shown in-Ghubb'Patent'No. 1,068,411 andin'Presser Patent .No. -1,-l 1-7.-,-240 1for example. The bath 20 contains electrodes .29, 29-and the bath 60 contains electrodes 69, "69 which ado,notjcome into-.directicontact with:the wires. The elecutmdes are eonnectedito a commonsource of direct curnl'qn ii61 l shown-in F s Simetthetwirerl0ll passesifrom the die 10 to thetguide roller 12, for example, in a substantially straight horizontal path and since the wire is under a very large tension which is great enough to draw the same, the said wire may be caused to vibrate all along the length between the die 10 and guide roller 12 by intermittently striking the same. One difliculty in plating wires is to obtain the desired rate of deposition (measured in amperes per square foot and expressed as current density,

70 for example). The limitation on current density is determined by the speed with which the ions in the plating solution can be replaced or recreated adjacent the cathode for deposition on the latter. -The c rinveiitional way of improving this condition is by agitatingthe solution, by mechanically holding and vibrating the cathode or by a combination of :both such means. According to this invention theplating. operation is carried. out 5 while the wire is under a high constant tension suflicient to draw said wire. Heretofore it was not considered feasible to plate wire while held under the high tension required to draw the same. This invention isbased on the discovery not only that sucha process is feasible'dO but that it has at least one added advantage, namely, that while under such tension the wire, may be made to act as its own vibrator. The wire when struck acts like a violin string. As shown in Figs. 1A, 1B and 2 the striking mechanism 90 for causing the wire 100 to 'l5 guide rollers or other means contact the wire between" the die 10 and guide roller 12. .The striking mechanism shown consists of a disk 91 held on rotating shaft 92. The disk 91 carries one or more fingers 93, 94 which move from a position below the line of travel of the wire 100 to a position above the line of travel so. that each finger 93, 94 strikes'the wire during each rotation. The shaft 92 is driven by suitable means such .as pulley 95 and belt 96. The tension required to hold the wire at its entrance end so that it can be vibrated according to the invention is possible only through a device capable of deforming the wire such as the die 10, oran equivalent means. The wire could be vibrated by other devices such as by electromagnetic means, etc. By this unusual method of vibrating and agitating, the current density has been increased to many times that which is possible without such vibrating step. For example, current densities as high as 3000 amps per square foot have been employed as compared with a maximum of about 200 amps per square foot ordinarily employed. The exact nature of the die 10 is not important as long'as the die 40 is capable of holding the wire under sufficient tension. Fig. 4 shows a conventional type of die 10 having an orifice 11 which can be employed. As shown in Fig. 2 a plurality (four shown) of wires 100 may be treated simultaneously the guide rollers 12, 13, 14 and 15 and take-up rollers 16, 17, 18 and 90 being offset with respect to each other. The wire 100 can be of any suitable size and subsequent to plating, it maybe redrawn to smaller diameter since the plating which is applied at a relatively high current density is very uniform and is very adherent to the base material. v

The following example illustrates how the process is carried out on an actual wire although it is understood that the example does not in any way limit the scope of the invention.

Example A .045" copper wire is drawn through a die 10 to reduce its diameter to .042" 'by an apparatus like that shown in Figs. 1A, 1B and 2 and drawn through a series of baths 20, 30, 40, 50, 60, 70 and 80. The speed at which the wire is pulled through the baths is from 3 to 200 feet per minute. In bath 20 the wire is cleaned with an electrolytic cleaning bath such as a batlr-of sodium phosphate at 180 F. Inbath 30 the wire is rinsed,- in

bath 40 it is dipped in 10% sulfuric acid, in bath 50 itisag'ain rinsed, 'in' 60 the wirebecomes the cathode and is plated with tin from ya tin plating bath, in bath the wire is again rinsed, at 90 the wire is periodically struck to cause it to vibrate and in bath the wire is given a hot water rinse to cause it to dry quickly before winding. The wire is drawn off and wound at 16. Thereafter the wire may be drawn down to a diameter of--.0ll" in twelve steps.

It will be seen that the invention provides a process and apparatus which, although it is directly contrary to the teachings of the prior art, provides unusual and unexpected advantages and a superior product.

We claim:

1. In an apparatus for electroplating wire, the combination comprising a series of baths including an electroplating bath horizontally arranged in substantially the same horizontal plane, a die adjacent a first end of said series of baths, means for feeding wire to said die, said die being-of smaller size than said wire whereby said die is adapted to resist movement of the wire therethrough, means adjacent the other end of said series of baths adapted to apply sufficient tension to the wire to draw said wire through said die, the horizontal path between said die and said wire drawing means being substantially unobstructed whereby the wire passing in said unobstructed path is electroplated while under a substantially uniform drawing tension, said baths having parallel slits at the ends thereof for the passage of said wire therethrough and means adjacent one of said baths of said series adapted to set the wire to vibrating in the direction of the slits in said baths under the natural vibration frequency determined by the tension on the wire and the distance between said die and said drawing means whereby said vibrations extend along the entire horizontal path between the die and the drawing means. 2. The apparatus as set forth in claim 1 in which the said means for setting the wire in vibration comprises at least one finger for periodically striking said wire.

3. In a method of electroplating wire, the steps comprising continuously passing said wire to a drawing die of smaller diameter than said wire so that the said die is adapted to hold the wire to permit the wire passing therethrough to be tensioned sufficiently to reduce the size thereof, applying sufiicient tension to the wire com- References Cited in the file of this patent UNITED STATES PATENTS 1,515,092 Cowper-Coles Nov. 11, 1924 1,601,642 Parker Sept. 28, 1926 2,293,810 Domm Aug. 25, 1942 2,370,973 Lang Mar. 6, 1945 2,447,531 Pierce Aug. 24, 1948 FOREIGN PATENTS France Mar. 28, 1927 

3. IN A METHOD OF ELECTROPLATING WIRE, THE STEPS COMPRISING CONTINUOUSLY PASSING SAID WIRE TO A DRAWING DIE OF SMALLER DIAMETER THAN SAID WIRE SO THAT THE SAID DIE IS ADAPTED TO HOLD THE WIRE TO PERMIT THE WIRE PASSING THERETHROUGH TO BE TENSIONED SUFFICIENTLY TO REDUCE THE SIZE THEREOF, APPLYING SUFFICIENT TENSION TO THE WIRE COMING FROM SAID DIE TO REDUCE THE SIZE THEREOF, SAID TENSION BEING APPLIED AT THE END OF A SUBSTANTIALLY UNOBSTRUCTED, STRAIGHT, HORIZONTALLY-SPACED PATH FROM SAID DIE, CONTINUOUSLY ELECTROPLATING SAID WIRE WHICH UNDER SAID TENSION AND WHILE TRAVELING IN SAID UNOBSTRUCTED PATH, AND MAINTAINING THE WIRE IN SUBSTANTIALLY CONTINUOUS VIBRATION BY INTERMITTENTLY STRIKING THE WIRE TO CAUSE IT TO VIBRATE ALL ALONG SAID SUBSTANTIALLY UNOBSTRUCTED PATH AT THE NATURAL VIBRATION FREQUENCY OF THE WIRE AS DETERMINED BY LENGTH AND THE HIGH TENSION OF DRAWING OF THE WIRE. 